The 2-D Collision Simulator is an adjustable-size file that displays nicely on smart phones, on tablets such as the iPad, on Chromebooks, and on laptops and desktops. The size of the Interactive can be scaled to fit the device that it is displayed on. The compatibility with smart phones, iPads, other tablets, and Chromebooks make it a perfect tool for use in a 1:1 classroom.

This Interactive is easy to use in order to analyze just about any type of collision, whether it be perfectly elastic or highly inelastic, one-dimensional or two-dimensional. A range of input parameters can be controlled to quickly determine their impact upon the collision. Numerous display parameters can be toggled on and off and utilized to analyze the essential principles that govern the  collision of objects.


Teaching Ideas and Suggestions:

This Interactive can be used at several times during a learning cycle on collisions and momentum conservation.  Our Collision Carts Interactive has long been a go-to simulation among physics teachers for many years. It's simplicity and accompanying student exercise sheets make it a reliable model for understanding momentum conservation for collisions occuring in one dimension. The Two-Dimensional Collision Simulator can be used in a similar manner for studying both perfectly elastic collisions in one dimension, hit-and-stick collisions, and every other one-dimensional collision in between the perfectly elastic and the perfectly inelastic types. The ability to vary the coefficient of restitution (COR) of the collision combined with the Kinetic Energy displays allows one to gain insight into the continuum of collisions from inelastic to perfectly elastic.

While the simulation can be used to study one-dimensional collisions, it really shines as a tool for understanding elastic collisions and two-dimensional collisions. The speed and direction of the two objects can easily be changed by dragging them around the collision space. The arrowhead of the velocity vector of each object is a hot spot that can be dragged to change the magnitude and direction of the velocity. The simulator provides the ability to view the velocity components before and after the collision and/or the momentum or momentum components before and after the collision. Two tables are displayed to tabulate values of kinetic energy and momentum of the two objects and the system before and after the collision. The movement of the center of mass of the system of two objects can be viewed.

The ease at which each objects' parameters can be modified (by using the sliders in the Collision Parameters control panel or by simply dragging the objects and their velocity vectors in the Simulation Window) makes this Interactive an effective tool for quickly analyzing a collision. Students can use the simulation to explore or utilize the Activity Sheets that we have provided for a more guided experience.  We have provided two such Activity Sheets; we plan to produce more. The activities will have the greatest impact on students with comfortable to strong math skills. They are ...


Related Resources

There are numerous resources at The Physics Classroom website that serve as very complementary supports for the Two-Dimensional Collision Simulator. These include:
  • The Calculator Pad
    Our Calculator Pad tool is sourced with more than 2000 ready-to-use Physics word problems. Each problem contains randomized numbers, an answer field for inputting an answer, immediate feedback, and (often) problem-specific help. Our Momentum and Collisions section has three particularly applicable problem sets associated with elastic collisions and two-dimensional collisions. See Problem Sets MC13, MC14, and MC15 at The Calculator Pad.

  • Minds On Physics Internet Modules:
    The Minds On Physics Internet Modules include a collection of interactive questioning modules that help learners assess their understanding of physics concepts and solidify those understandings by answering questions that require higher-order thinking. Assignments MC5, MC6, MC7, MC8, MC9, and MC10 of the Momentum and Collisions module provide great complements to this Interactive. They are best used in the middle to later stages of the learning cycle. Visit the Minds On Physics Internet Modules.
  • Animation: Numerous GIF Animations at The Multimedia Physics Studios
    The Momentum and Collisions section of the Multimedia Physics Studios has several instructive animations that depict the collisions of objects. Visit the Multimedia Physics Studios.

  • Curriculum/Practice: Several Concept Development worksheets at the Curriculum Corner will be very useful in assisting students in cultivating their understanding, most notably ...

    Action-Reaction and Momentum Conservation
    Collision Analysis

    Visit the Curriculum Corner.

  • Labwork: 
    Simulations should always support (never supplant) hands-on learning. The Laboratory section of The Physics Classroom website includes several hands-on ideas that complement this Interactive. Four notable lab ideas include ...

    Before and After Lab
    Sand Balloon Lab
    Inelastic Collision Analysis
    Two-Dimensional Collision

    Visit The Laboratory.
  • Science Reasoning Activities:
    Science classrooms should be filled with reasoning activities. There is one related activity in the Momentum and Collisions section of the Science Reasoning Center that will challenge students to employ close reading, data analysis, and logical reasoning. The activities are named ...


    Visit the Science Reasoning Center.

Additional resources and ideas for incorporating the Two-Dimensional Collision Simulator into an instructional unit on collisions can be found at the Teacher Toolkits section of The Physics Classroom website.  Visit Teacher Toolkits.



We owe a special thanks to Physics teacher Martin Kirby for donating the Two-Dimensional Collision Simulator to our Interactives collection. Martin has contributed many other simulations to our Interactives collection. You can view them all by visiting our page listing all Martin Kirby Simulations. Or visit Martin's website ( to learn more.



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